Cardiorespiratory Nursing Interventions

Cardiorespiratory Nursing Interventions

Cardiorespiratory nursing interventions require precision, critical thinking, and rapid clinical decision-making. DHA nursing exam questions frequently present scenarios involving chest tube maintenance, tracheostomy emergencies, and the interpretation and management of life-threatening cardiac rhythms. This section covers ECG interpretation, chest tube management, and tracheostomy care.

1. ECG Interpretation and Arrhythmia Management

Electrocardiogram (ECG) interpretation is a fundamental skill for nurses working in acute and critical care environments.

The Cardiac Conduction System

The electrical impulse originates in the Sinoatrial (SA) node (primary pacemaker, rate 60–100 bpm), travels through the intra-atrial pathways to the Atrioventricular (AV) node (delaying the impulse to allow ventricular filling, pacemaker rate 40–60 bpm), then down the Bundle of His, left and right bundle branches, and finally to the Purkinje fibers (pacemaker rate 20–40 bpm).

Basic Components of an ECG Complex

• P Wave: Represents atrial depolarization.
• PR Interval: Represents the time it takes for the impulse to travel from the SA node through the AV node. Normal: 0.12 to 0.20 seconds (3 to 5 small boxes).
• QRS Complex: Represents ventricular depolarization. Normal: < 0.12 seconds (less than 3 small boxes).
• ST Segment: Represents the period between ventricular depolarization and repolarization. Elevated or depressed ST segments indicate myocardial ischemia or injury.
• T Wave: Represents ventricular repolarization.
• QT Interval: Represents the total time for ventricular depolarization and repolarization. Normal: typically 0.36 to 0.44 seconds (prolongation increases the risk of Torsades de Pointes).

Method for Determining Heart Rate

On a standard 6-second strip, count the number of R-R intervals (QRS complexes) and multiply by 10. For regular rhythms, divide 1500 by the number of small boxes between two consecutive R waves.

Key Arrhythmias and Interventions

Nurses must recognize the following rhythms on the exam and know their immediate clinical priorities:

1. Sinus Bradycardia: Heart rate < 60 bpm with normal sinus morphology.
   • Intervention: If asymptomatic, monitor. If symptomatic (hypotension, dizziness, syncope, chest pain), administer Atropine 1 mg IV push (can repeat every 3–5 minutes up to a maximum dose of 3 mg) as the first-line medication. If ineffective, prepare for transcutaneous pacing or epinephrine/dopamine infusions.
2. Sinus Tachycardia: Heart rate > 100 bpm with normal sinus morphology.
   • Intervention: Identify and treat the underlying cause (e.g., pain, fever, dehydration/hypovolemia, hypoxia, anxiety).
3. Atrial Fibrillation (A-fib): Characterized by chaotic, rapid atrial activity with no discernible P waves (replaced by fibrillatory waves) and an irregularly irregular QRS rhythm.
   • Clinical Risk: Loss of atrial kick leads to blood stasis in the atria, creating a high risk for mural thrombus formation and systemic thromboembolism (ischemic stroke).
   • Interventions:
     • Rate Control: Beta-blockers (e.g., Metoprolol), Calcium Channel Blockers (e.g., Diltiazem), or Digoxin.
     • Anticoagulation: Warfarin or Direct Oral Anticoagulants (DOACs; e.g., Apixaban) to prevent stroke.
     • Rhythm Control: Pharmacological (Amiodarone) or electrical cardioversion.
     • DHA Exam Alert: If A-fib has been present for more than 48 hours, electrical cardioversion must not be attempted unless the patient has been anticoagulated for at least 3 weeks or a transesophageal echocardiogram (TEE) rules out atrial thrombi. Cardioverting a patient with an active atrial clot can cause a massive embolic stroke.
4. Ventricular Tachycardia (V-tach): A rapid, regular rhythm originating in the ventricles, characterized by wide, bizarre QRS complexes (> 0.12 seconds) and absent P waves. Rate is typically 150–250 bpm.
   • Intervention based on Pulsation:
     • With a Pulse: Assess hemodynamic stability. If stable, administer antiarrhythmics (e.g., Amiodarone infusion). If unstable (hypotension, chest pain, dyspnea), perform immediate Synchronized Cardioversion.
     • Pulseless: Treat exactly like Ventricular Fibrillation. Activate emergency response, begin high-quality CPR, and deliver an unsynchronized shock (defibrillation) as soon as the defibrillator is ready.
5. Ventricular Fibrillation (V-fib): A chaotic, quivering ventricular rhythm with no organized electrical activity and no mechanical contraction. The client is unresponsive, pulseless, and apneic.
   • Priority Intervention: Immediate CPR and Defibrillation. Defibrillate at 120–200 Joules (biphasic) or 360 Joules (monophasic) as soon as the machine is available. Administer Epinephrine 1 mg IV/IO every 3–5 minutes and Amiodarone (300 mg bolus, then 150 mg) for refractory V-fib.
6. Asystole: Complete absence of electrical and mechanical activity (flatline).
   • Intervention: High-quality CPR, Epinephrine 1 mg IV push, and identification of reversible causes (H's and T's). Do NOT defibrillate. There is no electrical activity to reorganize; shocking asystole causes myocardial damage and does not restore a rhythm.

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2. Chest Tube Management

Chest tubes are inserted into the pleural space to remove air (pneumothorax), blood (hemothorax), or fluid (pleural effusion) to restore negative intrapleural pressure and re-expand the lung.

The Three-Chamber Drainage System

1. Collection Chamber: Receives fluid and air from the pleural space.
   • Nursing Action: Document the volume, color, and consistency of the drainage hourly in the immediate postoperative period, then every 4 to 8 hours. Report drainage that is > 100 mL/hour, or if it suddenly changes from serosanguinous to bright red blood.
2. Water Seal Chamber: Contains 2 cm of sterile water and acts as a one-way valve, allowing air to escape from the pleural space but preventing atmospheric air from entering.
   • Tidaling: The normal fluctuation of the water level with respiration (rises during inspiration and falls during expiration in a spontaneously breathing patient; reversed in mechanically ventilated patients).
     • Clinical Note: Tidaling stops when the lung has fully re-expanded, or if there is an obstruction, kink, or clot in the chest tube system.
   • Bubbling:
     • Intermittent Bubbling: Normal when air is being evacuated from the pleural space (e.g., in a patient with an active pneumothorax during expiration, coughing, or sneezing).
     • Continuous Bubbling: Abnormal. Indicates an air leak in the system. The nurse must check all connections, ensure they are taped securely, and briefly clamp the tube near the insertion site. If the bubbling stops, the leak is in the patient's pleural space or at the insertion site; if it continues, the leak is in the drainage tubing or collection unit itself.
3. Suction Control Chamber: Regulates the amount of suction applied to the pleural space.
   • Dry Suction: Regulated by a dial on the unit (usually set to –20 cm H2O).
   • Wet Suction: Regulated by the height of sterile water in the suction column (usually filled to the –20 cm mark).
     • Clinical Note: Gentle, continuous bubbling in the wet suction chamber is a normal finding indicating that suction is active. If there is no bubbling, check if the suction source is turned on and connected, or if water has evaporated (add sterile water to maintain the level).

Nursing Management and Emergency Protocols

• Positioning: Keep the drainage system below the level of the patient's chest at all times to prevent backflow of fluid.
• Assessment: Never strip or milk the tubing, as this generates excessively high negative pressures that can damage lung tissue. Avoid clamping the tube unless specifically ordered (e.g., to check for leaks, change the system, or test tolerance before removal) because clamping can quickly lead to a life-threatening tension pneumothorax.
• Bedside Safety Equipment: Always keep sterile water, sterile occlusive (Vaseline) dressings, hemostats, and waterproof tape at the bedside.
• Emergency Scenarios:
  1. If the chest tube is accidentally dislodged from the patient: Immediately cover the insertion site with a sterile occlusive dressing and tape it on three sides. This creates a flutter-valve effect, allowing air to escape during expiration but preventing atmospheric air from being drawn in during inspiration, avoiding a tension pneumothorax. Notify the healthcare provider immediately.
  2. If the chest tube becomes disconnected from the drainage system: Do not clamp the tube. Immediately submerge the distal end of the chest tube in 2 cm of sterile water or normal saline. This immediately re-establishes a temporary water seal, preventing atmospheric air from entering the pleural space while a new drainage system is set up.

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3. Tracheostomy Care

A tracheostomy is a surgically created opening (stoma) in the trachea to establish an airway.

Types of Tracheostomy Tubes

• Cuffed Tubes: Contain an inflatable cuff that seals the trachea. Required for patients on mechanical ventilation (to prevent air leaks) or those at high risk of aspiration.
  • Safety Parameter: Cuff pressure must be maintained between 20 and 25 cm H2O (or 15–20 mmHg) to prevent tracheal necrosis (from excessive pressure) or aspiration (from under-inflation).
• Uncuffed Tubes: Used for long-term airway management in patients who are awake, alert, breathing spontaneously, and have an adequate gag and cough reflex.

Suctioning Protocol

Suctioning is performed to clear secretions and maintain airway patency, but it should only be performed when clinically indicated (e.g., visible secretions, crackles over trachea, increased peak airway pressures, coughing, restlessness) rather than on a scheduled basis, as frequent suctioning causes mucosal damage and bronchospasm.

1. Preparation: Explain the procedure. Hyper-oxygenate the patient with 100% oxygen for 30 to 60 seconds before suctioning.
2. Insertion: Using strict sterile technique, insert the suction catheter without applying suction until the catheter meets resistance (at the carina) or the patient coughs. Withdraw the catheter 1–2 cm before applying suction.
3. Suctioning: Apply intermittent suction ONLY while withdrawing the catheter. Rotate the catheter between the thumb and forefinger during withdrawal.
4. Time Limit: Limit suctioning to a maximum of 10 to 15 seconds per pass to prevent severe hypoxemia and vagal stimulation (which causes bradycardia).
5. Frequency: Allow the patient to recover for 1 to 2 minutes between passes; limit suctioning to a maximum of 3 passes per session.

Cleaning and Dressing Changes

Performed at least once per shift or whenever soiled.

• Use sterile technique to clean the stoma and inner cannula.
• Clean the stoma with half-strength hydrogen peroxide or normal saline (per facility policy) and rinse with normal saline. Dry the skin thoroughly to prevent maceration.
• Changing Tracheostomy Ties: To prevent accidental decannulation, secure the new ties in place before removing the old ones, or have a second nurse assist to hold the tracheostomy tube securely in place throughout the tie change.

Accidental Decannulation Emergency Management

• If decannulation occurs within the first 72 hours postoperatively: This is a critical medical emergency because the surgical tract has not matured and can easily collapse, leading to rapid airway occlusion.
  • Action: Call for help immediately. Place the patient in a supine position and hyperextend the neck to open the airway. Locate the spare tracheostomy tube of the same size (or one size smaller) kept at the bedside, insert the obturator into the outer cannula, and gently attempt to insert the tube into the stoma. Immediately remove the obturator after insertion.
  • If unable to insert: Cover the stoma with a sterile dressing and ventilate the patient using a bag-valve-mask (Ambu bag) over the nose and mouth while waiting for the emergency response team.
• If decannulation occurs in a mature tracheostomy tract (> 7 days): Gently insert a clean or sterile spare tube using the obturator. Secure it in place and assess breath sounds.